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Inter-domain interactions influence the stability and catalytic activity of the bi-domain protein tyrosine phosphatase PTP99A

Madan, Lalima L and Goutam, Kapil and Gopal, B (2012) Inter-domain interactions influence the stability and catalytic activity of the bi-domain protein tyrosine phosphatase PTP99A. In: BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS, 1824 (8). pp. 983-990.

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Official URL: http://dx.doi.org/10.1016/j.bbapap.2012.05.001

Abstract

The two protein tyrosine phosphatase (PTP) domains in bi-domain PTPs share high sequence and structural similarity. However, only one of the two PIP domains is catalytically active. Here we describe biochemical studies on the two tandem PTP domains of the bi-domain PTP, PTP99A. Phosphatase activity, monitored using small molecule as well as peptide substrates, revealed that the inactive (D2) domain activates the catalytic (D1) domain. Thermodynamic measurements suggest that the inactive D2 domain stabilizes the bi-domain (D1-D2) protein. The mechanism by which the D2 domain activates and stabilizes the bi-domain protein is governed by few interactions at the inter-domain interface. In particular, mutating Lys990 at the interface attenuates inter-domain communication. This residue is located at a structurally equivalent location to the so-called allosteric site of the canonical single domain PIP, PTP1B. These observations suggest functional optimization in bi-domain PTPs whereby the inactive PTP domain modulates the catalytic activity of the bi-domain enzyme. (C) 2012 Elsevier B.V. All rights reserved.

Item Type: Journal Article
Additional Information: Copyright for this article belongs to Elsevier
Keywords: Silent domain; Catalytic activity; Activation; Phosphatase; Allosteric site; Domain-domain interaction
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited: 08 Aug 2012 08:41
Last Modified: 08 Aug 2012 08:41
URI: http://eprints.iisc.ernet.in/id/eprint/44912

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